T-shaped ceiling profile with suspension holes

Description

BACKGROUND OF THE INVENTION

[0001] The invention relates to improvements in grid tees and in particular to suspension holes for such articles.

[0002] GB 1154560 A describes a grid structure for a suspended ceiling. The structure comprises a plurality of main beams. The main beams include a plurality of spaced perforations to aid in suspending the beam from a main ceiling, and apertures in which additional cross beams may be engaged.SUMMARY OF THE INVENTION

[0003] The invention is defined by the claims.

[0004] As disclosed, the location and form of suspension holes, typically in main tees, are arranged to facilitate erection of a grid and in some instances improve its load carrying capacity. As conventional, the suspension holes are located in the vertical, central web extending between an upper reinforcing bulb and a lower panel supporting flange. Holes closest to cross tee slots in the web are horizontally elongated to facilitate threading assembly of hanger wire therethrough, particularly in poorly illuminated conditions. Additionally, the holes are spaced horizontally and vertically away from the cross tee slot than has been customary to enable an installer to more easily finger guide a connector into the slot. Still further, vertical displacement of the hanger holes from the cross tee slots minimizes the risk that a cross tee connector sliding along the main tee during installation will intersect a hanger hole and confuse the installer, thinking the connector is aligned with a cross tee slot or will be obstructed by a hanger wire. Advantageously, the holes are centered 2.54 cm (one inch) above the grid face, eliminating measurements in fractions when establishing the plane of the grid face.

[0005] The foregoing improvements in the arrangement of the main tee suspension holes can improve the productivity of an installer. This improvement can drive sales ultimately to the manufacturer.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a side view of a portion of the length of the inventive grid main tee; FIG. 2 is a cross-section of the grid tee of FIG. 1; and FIG. 3 is a diagrammatic plan view of a manual punch tool illustrated in two places. DESCRIPTION OF THE PREFERRED EMBODIMENT

[0007] A main tee or runner 10, typically supplied in 12 foot lengths, (3,600 mm or industry metric equivalent) is used with cross tees 15 (FIG. 1) to form a suspended ceiling grid. The grid supports rectangular panels, lights, HVAC diffusers and other utilities. As is traditional, the main tees 10 are suspended from superstructure with steel hanger wire, typically 12 gauge. As shown in FIG. 2, the tee 10 made of sheet metal has an upper reinforcing bulb 11, double layer web 12 and lower flange 13 that include a cap strip 14.

[0008] The illustrated main tee 10 has cross tee receiving slots 16 conventionally spaced 6 inches (150 mm) apart, along the length of the tee.

[0009] Situated symmetrically from a cross tee slot 16 are hanger holes 17, 18 in the web 12. Holes 17 adjacent a slot 16 are oblong while outlying holes 18 are round. The width of the holes 17 is preferably the same as the diameter of the holes 18 (for instance .219 in.; 5.6 mm) and the elevation from the tee face, provided by the cap strip 14, of both the oblong and round holes 17, 18 is the same.

[0010] Inspection of FIG. 1 shows that the lowermost edges of both the oblong and round holes 17, 18 is above the upper extremity of the cross tee slot 16. This construction facilitates assembly of the cross tee connectors in the slots 16. With a hanger wire in either holes 17 or 18, the risk that a cross tee connector will be obstructed by a hanger wire in any of the adjacent holes 17, 18 when the cross tee assembly motion includes a sideways or lateral component such as when a cross tee end is slid over the flange 13 of the main tee 10.

[0011] Installers favor using the oblong holes 17, particularly at low illumination sites since it is easier to thread a hanger wire through it than the round hole 18, the area of the oblong hole being larger.

[0012] A hanger wire in an oblong hole 17 can be shifted horizontally in the hole away from the slot 16 with low force. When an installer uses a finger of one hand on the back side of a main tee 10 to guide a cross tee end connector to a slot 16 by instinctive knowledge of the location of the installer's finger and to feel the connector in the slot, he can displace the hanger wire in the oblong hole 17 for greater finger access to the slot 16.

[0013] Referring to FIG. 3, a manually operated cross tee slot punch 21 is diagrammatically illustrated. The punch 21 known in the art, operates in a manner analogous to a manual paper punch; when a handle 22 is depressed, a punch having the cross section of the slot 16 is pressed through the main tee web 12. An indexing arm 23 has a pin 24 that can be located in either a hole 18 or an oblong hole 17. The oblong hole 17, with the pin 24 at the end of the hole 17 adjacent the cross slot 16 positions the arm 23 and slot punch 21 at a nominal dimension, preferably an even two inches from the adjacent slot 16. When the indexing arm pin 24 is located in the round hole 18, the punch 21 is centered at another nominal even dimension such as three inches. Equivalent even metric dimensions can be, for instance, 5 cm and 8 cm. In the illustrated case, hole 18 is 2.54cm (one inch) from the far end of the adjacent oblong hole 17. Offsets between slots of 5.08 cm (two inches) or 7.62 cm (three inches) on both sides of an original factory slot 16 yield popular spacings of 10.16 and 15.24 cm (4 and 6 inches) for lighting and / or air ducts.

[0014] The slot punch 21 can be provided with two arms 23 or can be positioned on both sides of a main tee 11 to produce holes 17, 18 symmetrically on both sides of a factory slot.

[0015] It should be evident that this disclosure is by way of example and that various changes may be made by adding, modifying or eliminating details without departing from the fair scope of the teaching contained in this disclosure. The invention is therefore not limited to particular details of this disclosure except to the extent that the following claims are necessarily so limited.

Claims

1. A main tee (10) for a suspended ceiling formed of metal sheet and having an upper reinforcing bulb (11), a lower flange (13) and a web (12) between the bulb (11) and flange (13), the web (12) having evenly spaced, generally vertical cross tee receiving slots (16) along a length of the tee (10) and a series of suspension wire receiving holes (18, 17) along the length of the tee, the lowermost edges of the holes being above a highest extremity of the cross tee slots (16), characterized in that the suspension receiving holes including round holes (18) and oblong holes (17) adjacent to the cross tee slots (16).

2. A main tee (10) as set forth in claim 1, wherein said holes (18, 17) are symmetrically arranged about said cross tee slots (16).

3. A main tee (10) as set forth in claim 1, wherein the oblong holes and the round holes have a same elevation above the flange (13).

4. A main tee (10) as set forth in claim 1, wherein the oblong holes (17) are disposed between the round holes (18) and the cross tee receiving slots (16).

5. A main tee (10) as set forth in claim 1, wherein a spacing between adjacent round (18) and oblong holes (17) is an even dimension.

6. A main tee (10) as set forth in claim 1, wherein oblong (17) and round holes (18) are symmetrically disposed around the cross tee receiving slot (16) and a distance between a round hole (18) and cross tee slot (16) is less than the height of the main tee (10).